Mechanical properties of fiber reinforced plastics

,Composite materials posses’s the characteristics of high stiffness andstrength to weight ratios which are desirable for advanced engineeringapplications. GFRP cross-ply laminated composites are commonly used in thedifferent engineering structures. Understanding of both mechanical and fracturebehavior of these GFRP composites are very important since many of thesestructures are primary load-bearing components in the design.In this work, the effect of fiber volume fraction on the tensile mechanicalproperties (uo, Vxy and E) of GFRP cross-ply laminated specimens (0/90/6).have been examined theoretically and experimentally. The tensile mechanicalproperties were determined theoretically by two methods, classical laminationtheory and kelly theory. The effect of fib er volume fraction vf% and crack lengthto depth ratio (a/w) on fracture toughness of GFRP cross-ply laminatedspecimens have also been studied theoretically and experimentally. Thetheoretical predictions were determined by using [point stress criterion andaverage stress criterion] models. Comparisons were made between thetheoretical and experimental results. It was found that the tensile mechanicalproperties of GFRP cross-ply laminated composite increase with increasing fibervolume fraction. This study show that GFRP cross-ply composite laminateshave a relatively poor impact strength. The study show that the GFRP cross-plylaminated composite are notch sensitive material. The fracture toughness ofGFRP cross-ply composite can be considered as a material property for 0.2<a/w <0.6. The scanning electron microscope examination indicate that eachfiber volume fraction of GFRP composite have a unique fracture andmicrostructural characteristics.